Revert "Use VncAuth as the default security type, ..."

This reverts commit 39d7dc043afcf6f94b9c16942765fdb9a6a3202e.

We should be secure by default, even if it might cause a performance
hit. Those who wish to make that trade off are more likely to notice
the lack of performance than others noticing the lack of security.
1 file changed